Plunger driving mechanisms for agricultural balers typically comprise a flywheel. Depending on the type of baler, this flywheel can have different dimensions. For example a large baler will have a substantially heavy flywheel where a small baler can be provided with a smaller flywheel. Existing flywheel parking brake mechanisms for agricultural balers comprise a belt that is guided over the flywheel, which belt is connected to the frame of the baler in a fixed position, and comprising tightening means that are provided to tighten, or loosen, the belt around the flywheel. Thereby, by tightening the belt (having a fixed position) around the flywheel, the friction between the flywheel (that rotates) and the belt (that is in a fixed position) increases, thereby stopping the rotation of the flywheel. By loosening the belt, the friction between the flywheel and the belt decreases so that the flywheel can rotate.
U.S. Pat. No. 3,006,207 discloses an agricultural baler having a braking mechanism acting on the drive train of the baler. A brake shoe engages the edge of the outer disc of the rear pulley.
An advantage of these existing parking brake mechanism is that the braking force can be exactly set at an optimal predetermined braking force. Furthermore, this predetermined braking force can be maintained over a long period of time (several days or several weeks). Thereby, the braking mechanism proves to be reliable as a parking brake, where a braking force must be maintained over a longer period of time without losing too much brake force. A further advantage of this braking mechanism is that it can be used to slow down a rotating plunger driving mechanism.
A drawback of the above known braking mechanism is that it is less wear resistant, and that frequent maintenance interventions are required to keep the braking mechanism reliable. A further drawback is that often the braking mechanism cannot be operated from a remote place.
US 2003/0106754 shows a hydraulic brake system for small utility and recreational vehicles which undergo frequently stopping, such as golf cars and the like, for which it is important to be capable of holding the vehicle in a stopped position when on an upwardly or downwardly inclined grade. The brake system has a hydraulic accumulator that stores much of the energy generated upon brake pedal depression and a booster that automatically boosts the energy storage capacity of the accumulator during the first braking cycles to compensate for e.g. volumetric changes in the system that might take place during prolonged periods of non-use under dropping-temperature conditions. The solution proposed in this document is however very complex and expensive.